writes "As it approaches Christmas I'm in the process of adding a geek touch to my goldfish tank and need some ideas from the Slashdot community. So far I have collected a few static plastic models, such as the Enterprise NCC-1701, R2D2 and a Supreme Dalek to glue to the bottom of the tank; however I would also like to add some more dynamic items. I already have a USB controlled switchable power socket connected to a Raspberry Pi to control the main tank light remotely and was thinking this might be expanded to control some LEDs, motors and maybe even some Nixie tubes. However I'm unsure of the best way to interface these together and also wondering what precautions are needed because the water in the tank may not be pure? I look forward to hearing ideas from the community and am interested in how you would approach the problem."